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Experiment Reveals How Caffeine Could Power Your Gadgets

If you need that cup of coffee to get going in the morning, you’re not alone. According to a 2013 survey by the National Coffee Association, 83 percent of people in the U.S.—the world’s leader in coffee consumption—drink coffee, and 63 percent of Americans have at least a cup a day.

We may someday give our gadgets a boost with caffeine.

Earthwatch student fellowship winner Neel Patel observed this trend in his high-school classmates: “They are addicted to caffeine,” he says. “It’s their lifeblood for staying awake to work on all the homework from AP classes.” This observation gave him an idea: what if caffeine could power something other than a person?

Charging Cellphones with Caffeine

Neel wanted to solve a particular problem, one he first encountered while visiting family in India. A first-generation Indian-American who lives in Gardena, California, Neel stayed with relatives for six weeks in Jespore, a village about 150 miles north of Mumbai. It was too remote for traditional landline coverage, he discovered, and everyone had at least one cellphone. “I was shocked because even the poor farmers had two phones,” he says. Keeping the cellphones charged, though, proved challenging: “Every other day, there were power outages, and the power fluctuated even when it was active.”

The villagers needed regular electricity to stay connected. Neel thought of an alternative energy source he’d read about in a magazine: microbial batteries, which harness the electricity generated by microscopic organisms like bacteria as they metabolize their food. To make such a battery, he’d need soil, which naturally contains bacteria; something to put it in; and conductive materials to capture the flow of electrons produced as the microbes digested.

Researchers have investigated this technology for years, but the voltage produced is too low to be of much applied use. What if, thought Neel, the same substance that fueled his classmates could give the microbes a boost? “Caffeine has been tested on E. coli, and strains have been produced that can thrive off caffeine,” he says. “This gave me the idea of attempting to increase the efficiency of microbial batteries using caffeine.”

Neel shows off his battery at the Los Angeles County Science Fair.

Ringing in Success at the Science Fair

Neel tested this idea for the 2014 Los Angeles County Science Fair: he constructed his own microbial batteries with soil from his back yard, plastic cups, and straws.
He then ran a test to compare a control battery—one that contained unadulterated soil—to batteries to which he added different amounts of powdered caffeine, which is available as an athletic supplement. He first measured the voltage output of these batteries over a period of 15 minutes, but the data was “too close to call.” So he decided to collect his measurements over a longer period of time, 48 hours. Then a clear pattern emerged.

A little stimulant in the soil did indeed increase the voltage output. But it wasn’t simply a matter of more caffeine equaling more power. “Initially, I thought that caffeine would increase the power, but I didn’t think that after a certain point it would decline. And I noticed that in my results,” says Neel. He concluded that the optimal amount of the stimulant was 0.6 grams of caffeine per 20 grams of soil, which more than doubled the millivolts per second produced by the caffeine-free control battery. But when he added 0.9 grams—the highest value he tested—the output dropped. “It actually declined to a level that was equivalent to the control,” he says. “I think that, after a certain point, the caffeine became too toxic for the microorganisms.”

The Future for Microbes

Neel will begin his senior year in the fall of 2014, and then he plans to start college with a major in neuroscience. He hasn’t decided if he wants to stay in California or go to an out-of-state school.

Before he embarks on the next phase of his education, he will spend a week experiencing the life of a scientist on an Earthwatch Expedition. He and his science fair entry captured the attention of special award judges from Earthwatch, who award fellowships generously funded by donors Peter and Helen Bing at the Los Angeles County Science Fair each year. Along with three other outstanding students, Neel was hand-selected to receive a student fellowship on the expedition of his choice.

Neel will join Tracking Costa Rica’s Mammals, where he’ll follow tapirs and monkeys through the wilderness and interview Costa Rican farmers about these animals to find out if Costa Rica’s agricultural policies are good for wildlife. This subject interests him, he says, because his relatives in India are farmers, and he wants to learn more about agriculture and the people who depend on it in other parts of the world. Costa Rica will become the second country he has visited outside the U.S.

As for microbial batteries, Neel sees a bright future. He says the technology needs “a lot of development” to find out how to produce a significant and steady amount of electricity. If the researchers behind this work have Neel’s vision and dedication, we could soon be drinking our coffee and feeding our batteries with it, too.